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P1631 Cadillac Code - Theft Deterrent Start Enable Signal Not Correct

- Code Popularity: 18,147 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC P1631 Cadillac?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Perform security relearn procedure
  • Faulty Ignition switch assembly
  • Ignition switch assembly harness is open or shorted
  • Ignition switch assembly circuit poor electrical connection
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How to Fix the DTC P1631 Cadillac?

Review the 'Possible Causes' mentioned above and visually examine the corresponding wiring harness and connectors. Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

Code Tech Notes

Security Relearn Procedure:

-Insert the key, attempt to start the vehicle, and leave the key in the ON position.
In some vehicles, the Battery and Security light will blink for several seconds, and then shut off. Then the Security light will then remain ON. Leave the ignition ON until the Security light goes OFF. This will take more than 5 mins.
-When the Security light goes OFF, turn the ignition to the OFF position.
-Leave ignition OFF for 20 Seconds.
-Attempt to start the vehicle again and leave the key in the ON position.
-In some vehicles, the Battery and Security light will blink for several seconds, and then shut off. Then the Security light will then remain ON. Leave the ignition ON until the Security light goes OFF. This will take more than 5 mins.
-Turn the ignition to the OFF position for 20 Seconds.
-Attempt to start the vehicle again and leave the key in the ON position.
-In some vehicles, the Battery and Security light will blink for several seconds, and then shut off. Then the Security light will then remain ON. Leave the ignition ON until the Security light goes OFF. This will take more than 5 mins.
-Once this entire procedure has been completed (three times) your vehicle will start on the fourth attempt.

Note: Some vehicles perform the relearn in a different sequence. You may notice your security light, battery light, and abs light will alternate. Once the security light is left out of the sequence that is considered one step. Repeat the procedure two more times and on the fourth time, your vehicle will start.

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1631 Cadillac code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to charge between $75 and $150 per hour.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

Code P1631 Cadillac Description

The Body Control Module (BCM) sends the pre-release information to the Engine Control Module (ECM) via the serial data circuit. The ECM then sends a challenge to the BCM. Both the ECM and BCM perform a calculation on this challenge. If the calculated response from the BCM equals the calculation performed by the ECM, the ECM will allow the vehicle to start. The BCM follows this action by sending the remaining immobilizer data to the ECM. If the immobilizer data sent by the BCM matches that stored by the ECM, the ECM will allow the engine to remain running. The Diagnostic Trouble Code (DTC) will be set if the ECM receives incorrect immobilizer data from the BCM.
OBDII Code P1631 Cadillac - Theft Deterrent Start Enable Signal Not Correct - AutoCodes.com
P1631 Cadillac Code - Theft Deterrent Start Enable Signal Not Correct

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Code P1631 Cadillac comments

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